Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Reconstructing Western Australian white shark (Carcharodon carcharias) bycatch based on interviews with fishers

Stephen Taylor , Matias Braccini , Barry Bruce , Rory McAuley

Abstract

The assessment of fisheries-related impacts on protected species, such as white sharks (Carcharodon carcharias), is often hampered by a lack of historical catch information. In this study, historical catch estimates derived from interviews with fishers operating in the Western Australian Temperate Demersal Gillnet and Demersal Longline Fisheries (TDGDLF) were matched with fishing effort data reported in statutory fishing returns. Catch estimates obtained from interviewed fishers were extrapolated to account for total catch in two different ways, resulting in mean (95% confidence intervals) estimates of 1,232 (476–2,245) and 1,039 (505–2,096) white sharks between 1988 and 2012. These estimates were then used to reconstruct catches over a 60-year period, from the start of commercial gillnetting in the mid-1950s. The reconstructed catch trend reflected the history of gillnet fishing effort, peaking in the late 1980s at a level approximately four times greater than the estimated catch of ~30 sharks yr-1 in 2014. More than one third of interviewed fishers expressed doubts about the accuracy of self-reported white shark catch data, a requirement of current legislation. Given the benefits of reporting data from protected species bycatch, efforts to accurately record this information should be continued and be improved.

MF17140  Accepted 29 August 2017

© CSIRO 2017